Composition comprising a phosphate binder and its preparation

ABSTRACT

A binder, a composition, a product and a kit, as well as a process for preparing the binder and composition, are directed to a composition useful as an inorganic phosphate binder, which binder is characterized as having calcium silicate sites which are connected the one with the other by alumina-silica phosphate bonds, and a filler.

[0001] The present application is a continuation in part application ofInternational Application No. PCT/BEO1/00174, with an Internationalfiling date of Oct. 8, 2001, published in English under PCT Article21(2), this continuation in part application further claiming thebenefit of priority of International Application No. PCT/BE03/00121filed on Jul. 7, 2003, which designates the United States and at leastone other country.

FIELD OF THE INVENTION

[0002] The present invention relates to a composition comprising aninorganic binder, most precisely to an inorganic phosphate binder.

THE PRIOR ART

[0003] Inorganic phosphate binder have already been proposed in thepast.

[0004] For example in a previous patent application WO9903797 in thename of Metal Chemical and Haji Anas, a polymeric matrix is disclosed,said matrix comprising a binder formed by mixing an alkali metalsilicate aqueous solution with a powder comprising silico-aluminousreactive raw materials. A polymerization time of more than one hour ishowever necessary for reaching a sufficient hardening of the matrix.

[0005] It has also been proposed in U.S. Pat. No. 6,139,619 to form abinder by mixing a water soluble silicate with a water soluble amorphousinorganic phosphate glass in an aqueous medium. The hardening of thebinder requires the removal of water by a heat treatment.

[0006] In U.S. Pat. No. 4,375,551, an acid solution is prepared bymixing Al₂O₃.3H₂O with phosphoric acid, said acid solution being thenmixed with calcium silicate. The so obtained binder has after hardeningpoor mechanical strength.

[0007] U.S. Pat. No. 4,504,555 discloses an inorganic resin formed byreacting a first liquid component containing a mono aluminum phosphateor a mono magnesium phosphate, with a second liquid component containingmagnesium oxide and/or wollastonite and a dispersing agent. Inert fillercan be added to the first or second component. The inert filler(particles not participating to the reaction) can be SiO₂ particles. Theproduct prepared by this reaction is a resin in which adjacent calciumsilicate sites (wollastonite) bound by magnesium/aluminum phosphatebonds, not by alumina silica phosphate bonds.

[0008] U.S. Pat. No. 3,179,527 discloses a coating compositionformulated by adding silica or lime to an acidic solution of aluminumphosphate. Calcium silicate is then added to the composition. As statedin column 2 of said patent, the effect of added silica depends from theparticle size of the silica particles, fine silica particles formingopen cracks, while coarser particles do not produce such cracks. Thesilica particles are therefore not dissolved, otherwise the particlesize of the silica particle would have no influence on cracks. Thesilica is therefore used in this patent as filler. The use of silica ina prereacted composition is even not indispensable according to saidpatent, as it could be replaced by calcium silicate. Silica is thereforenot participating in the formation of bond between two adjacent calciumsilicate particles. The compositions of this patent have a long shelfstability, meaning that the hardening reaction is a slow process.

[0009] The present invention has for subject matter a binder which canbe sufficiently hardened within a term of less than 10 minutes and whichhas excellent mechanical properties. The inorganic binder of theinvention is characterized by calcium silicate sites connected the oneto the other by alumina-silica phosphate bonds.

DESCRIPTION OF THE INVENTION

[0010] The Binder

[0011] The inorganic binder of the invention is characterized by calciumsilicate sites which are connected the one with the other byalumina-silica phosphate bonds.

[0012] Advantageously, the calcium silicate sites are calcium metasilicate sites having a substantially acicular nature with alength/diameter ratio from 2/1 to 50/1, advantageously from 3/1 to 20/1.

[0013] Preferably, the calcium meta silicate sites has an average lengthfrom 10 μm to 10 mm, advantageously from 50 μm to 5 mm.

[0014] The calcium silicate sites act preferably as cross-linking sitesfor alumina-silica phosphate bonds.

[0015] According to an embodiment, the alumina-silica phosphate bondshave a weight ratio Al₂O₃/SiO₂ ranging from 0.3:1 and 10:1,advantageously from 0.6:1 and 6:1.

[0016] According to an advantageously embodiment, the weight ratiocalcium silicate sites/alumina-silica phosphate bonds is comprisedbetween 0.1 and 1. 1, advantageously between 0.3 and 0.9, preferablybetween 0.4 and 0.7.

[0017] The binder of the invention is suitable for preparing producthaving a light weight (such a weight from 70 to 140 kg/m³) or a heavyweight (such as weight of 2,000 kg/m³ or even more). Products of theinvention have high mechanical properties, such as compression strengthof more than 40N/mm², bending strength of more than 10 N/mm², etc.

[0018] The invention relates also to a composition and a productcomprising at least a binder according to the invention and at least onefiller and/or reinforced material.

COMPOSITIONS OF THE INVENTION

[0019] The compositions of the invention are composition beforehardening, after hardening, possibly after an after treatment, such as adrying step, a heating step, etc.

[0020] Compositions of the inventions are compositions comprising atleast a binder of the invention, and one or more fillers, inert fillerswith the binder.

[0021] The composition of the invention comprising at least:

[0022] an inorganic binder having calcium silicate sites which areconnected the one with the other by alumina-silica phosphate bonds, thecalcium silicate sites acting as cross-linking sites for thealumina-silica phosphate bonds with a weight ratio Al₂O₃/SiO₂ rangingfrom 0.3:1 to 10:1, advantageously from 0.6:1 to 6:1, and

[0023] a filler.

[0024] Examples of fillers or reinforced materials which can be mixedwith the binder before its preparation, during its preparation, beforeits hardening or during its hardening are:

[0025] waste materials, such as finely divided waste material, forexample fuel ashes, fly ashes, buildings waste materials, etc.

[0026] flake-like materials such as mica, etc.,

[0027] silica sand, silica flour,

[0028] coloring agents or materials, such as inorganic coloring agents,pigments, etc.

[0029] cellulose and/or protein base fibers, such as natural fibers,flax, chip, straw, hemp, wool fibers, etc.

[0030] synthetic fibers, such as organic synthetic fibers, inorganicsynthetic fibers, such as polyesters, polypropylene, glass and ceramicfibers, etc.

[0031] natural and synthetic organic base waste materials, such as sawdust, rice husk, straw and recycled organic waste,

[0032] natural fibers of mineral origin,

[0033] natural material, possibly treated (for example heat treated),such as perlite, vermiculite, etc.

[0034] etc.

[0035] mixtures of one or more of the above fillers.

[0036] Specific examples of possible fillers are:

[0037] rice husk,

[0038] waste recycle cardboard

[0039] shredded paper

[0040] rice husk/shredded paper composite

[0041] rice husk+waste recycle cardboard

[0042] pine needle

[0043] laminated elements, such as honeycomb board, normal cardboard,etc.

[0044] pigments

[0045] Additives can be added to the binder before its preparation,during its preparation, before its hardening or during its hardening,such additives are for example:

[0046] foaming agents, such as water peroxide, organic peroxide, etc.

[0047] viscosity regulating agent, such as superplasticizer

[0048] material for improving the impermeability or the water repulsionsuch as lignosulfonates and silica fume

[0049] etc.

[0050] According to an embodiment, substantially all calcium silicatesites of the inorganic binder are bound the one to the other byalumina-silica phosphate bonds.

[0051] According to a specific embodiment, the weight ratio calciumsilicate site/SiO₂ present in the alumina-silica phosphate bonds of theinorganic binder is greater than 1, advantageously greater than 1.5,such as 2, 3, 4, 5 or even more.

[0052] The calcium silicate particles are advantageously calcium metasilicate particles having a substantially acicular nature with alength/diameter ratio from 2/1 to 50/1, advantageously from 3/1 to 20/1.

[0053] The calcium meta silicate particles have preferably an averagelength from 10 μm to 10 mm, advantageously from 50 μm to 5 mm, such as100 μm, 300 μm, 500 μm, etc.

[0054] According to a preferred embodiment, the calcium silicateparticles act as cross-linking sites for alumina-silica phosphate bonds.It seems also that the presence of insoluble calcium silicate particlescatalyzes the formation of alumina-silica phosphate bonds.

[0055] For example, the weight ratio calcium silicateparticles/alumina-silica phosphate solution is comprised between 0.1 and1.1, preferably from 0.3 and 0.9, most preferably between 0.4 and 0.7.

[0056] Preferably, the composition comprises at least a siliconcontaining filler, most preferably silicon containing fibers with alength of less than 1000 μm.

[0057] The weight content of silicon containing fibers with a length ofless than 1000 μm in the composition after its hardening and afterremoval of the possible free water is advantageously at least 0.5%. Thesilica containing fillers, especially fibers, are advantageously treatedwith a water repellent agent, such as a water repellent coating of lessthan 10 μm. This coating is for example a fluoro silane coating.

[0058] It has now further been observed that by using specific filler,especially a combination of specific fillers, it was possible toincrease mechanical properties of the mixture binder/filler(s) and/orthe final appearance of the composition after its hardening and/or thefire resistance of the composition. For example, it was observed thatswelling of the product could be reduced or prevented after a waterabsorption.

[0059] The invention relates thus also to a composition comprising atleast:

[0060] an inorganic binder having calcium silicate sites which areconnected the one with the other by alumina-silica phosphate bonds, thecalcium silicate sites acting as cross-linking sites for alumina-silicaphosphate bonds with a weight ratio Al₂O₃/SiO₂ ranging advantageouslyfrom 0.3:1 and 10:1, preferably from 0.6:1 and 6:1, and

[0061] silicon containing fibers with a length of less than 1000 μm, theweight content of silicon containing fibers with a length of less than1000 μm in the composition after its hardening and after removal of thepossible free water being of at least 0.5% (i.e. a dry weight content).

[0062] It has been observed that the presence of at least 0.5% byweight, preferably at least 1% by weight of silicon containing fibers,advantageously silicon containing fibers non reactive with the binder orsubstantially non reactive with the binder, it was possible to preventthe formation of any cracks at the surface of the hardened composition,as well as advantageously in the body of the hardened composition, evenif the hardened composition has a high thickness, such as a thickness ofmore than 2 mm, advantageously of more than 5 mm, such as a thicknesscomprised between 10 mm and 50 mm.

[0063] Advantageously, the composition comprises silicon containingfibers with an average (in weight) length of less than 500 μm, theweight content of silicon containing fibers with an average length ofless than 500 μm in the composition after its hardening and afterremoval of the possible free water (free water is water present in thecomposition, such as in the hardened composition, but which can beremoved in a drying step at a temperature of 100° C.) being of at least0.5% (i.e. a dry weight content).

[0064] According to a preferred embodiment, the composition comprisessilicon containing fibers with an average (in weight) length of morethan 10 μm, advantageously of more than 20 μm, preferably comprisedbetween 25 μm and 300 μm, most preferably between 50 μm and 250 μm.

[0065] According to an advantageous embodiment, the silicon containingfibers with a length of less than 1000 μm, advantageously with anaverage (in weight) length of less than 500 μm, are substantially notreactive with the binder, preferably not reactive with the binder, i.e.acting as a pure filler. Substantially not reactive silicon containingfibers are fibers characterized in that less than 10% by weight,advantageously less than 5% by weight, preferably less than 1% byweight, most preferably less than 0.5% by weight, of the siliconcontaining fibers is chemically reacted with the binder, for making forexample one or more chemical bonds between fibers and the binder.

[0066] According to embodiments, after hardening and removal of freewater, the composition comprises from 1% up to 75% by weight,advantageously from 2% up to 25% by weight, silicon containing fiberswith a length of less than 1000 μm, advantageously with an average (inweight) length of less than 500 μm.

[0067] Silica containing fibers are for example natural fibers, possiblytreated, synthetic fibers, mineral fibers, and mixtures thereof. Naturalfibers are preferred, such as wood fiber, straw fiber, rice husk or branfibers, mixtures thereof. The natural fibers are advantageously heattreated, for example at temperature higher than 400° C., such as at atemperature higher than 700° C. or 800° C., advantageously in anatmosphere rich in Nitrogen or in a nitrogen atmosphere. Said heattreatment is preferably carried after a drying step. Rice bran or ricehusk are preferred silica containing fibers used in the composition ofthe invention, said fibers being advantageously defatted and dried. Whensaid fibers are burned and carbonized in a nitrogen gas rice branceramic fiber are produced. Possibly some phenolic resin is added to therice bran or rice husk before the carbonizing and burning step. Possiblythe phenolic resin can be mixed with rice bran so as to prepare or formrice bran containing fibers or filaments, the latter fibers or filamentafter drying being carbonized and burnt (for example at a temperature of300 to 1100° C. during a time sufficient for the formation of ceramics).The silica containing fibers are advantageously ceramic silicacontaining fibers. Such fibers, especially rice bran ceramic fibers,have a high strength, a high hardness, a low density, a low friction(hereby the fibers can easily flow the one with respect to the other,whereby facilitating the mixing step).

[0068] Silica containing fibers are advantageously treated with a waterrepellent agent, such as a water repellent coating of less than 10 μm.This coating is for example a fluoro silane coating.

[0069] According to a preferred embodiment, the composition furthercomprises silica flour with a particle size of less than 500 μm,advantageously comprised between 2 and 400 μm, the weight content ofsilica flour in the composition after its hardening and after removal ofthe possible free water being of at least 0.5%. Said silica flourcontent is advantageously comprised between 1 and 10% by weight of thecomposition after its hardening and removal of free water (water whichcan be removed with a heating step at a temperature of 100° C.) (i.e. adry weight content).

[0070] Preferably, the composition comprises silica flour with anaverage (in weight) particle size comprised between 2 and 100 μm,advantageously between 5 and 60 μm, preferably between 10 and 50 μm, theweight content of silica flour in the composition after its hardeningand after removal of the possible free water being comprised between 1and 10%, advantageously between 2 and 8%.

[0071] According to a more specific embodiment, the composition with orwithout (advantageously with) silica flour further comprisescrystallized alumina silicate particles which are substantially notreactive with the binder and which have an average (in weight) particlesize comprised between 5 and 100 μm, the weight content of crystallizedalumina silicate in the composition after its hardening and afterremoval of the possible free water being comprised between 1 and 10%,advantageously between 2 and 8%.

[0072] According to an advantageous embodiment, the weight ratio calciumsilicate site/SiO₂ present in the alumina-silica phosphate bonds isgreater than 1, preferably greater than 1.5.

[0073] Advantageously, the calcium silicate sites are calcium metasilicate sites having a substantially acicular nature with alength/diameter ratio from 2/1 to 50/1, advantageously from 3/1 to 20/1.

[0074] Preferably, the calcium meta silicate sites has an average length(average in weight) from 10 μm to 10 mm, advantageously from 50 μm to 5mm, such as 100 μm, 300 μm, 500 μm.

[0075] The calcium silicate sites act preferably as cross-linking sitesfor alumina-silica phosphate bonds.

[0076] According to an embodiment, the alumina-silica phosphate bondshave a ratio Al₂O₃/SiO₂ ranging from 0.3:1 and 10:1, advantageously from0.6:1 and 6:1.

[0077] According to an advantageously embodiment, the weight ratiocalcium silicate sites/alumina-silica phosphate bonds is comprisedbetween 0.1 and 1.1, advantageously between 0.3 and 0.9, preferablybetween 0.4 and 0.7.

[0078] The composition of the invention can also comprise one or morefurther filler(s) and/or reinforced materials.

[0079] The composition, as well as the binder of the invention can beused for attaching two elements together, i.e. as glue, heat resistantglue or sealant.

[0080] Product

[0081] The invention relates also to a product comprising at least ahardened layer comprising an inorganic binder of the invention asdisclosed hereinabove in the paragraph relating to the binder, butpreferably having the composition of the invention as disclosedhereinabove.

[0082] The binder/composition of the invention is suitable for preparingproduct having a light weight (such a weight from 70 to 140 kg/m³) or aheavy weight (such as weight of 2,000 kg/m³ or even more).

[0083] Products of the invention have high mechanical properties, suchas one or more of the following properties (preferably several of saidproperties): compression strength of more than 40N/mm², bending strengthof more than 10 N/mm², very low heat of combustion (less than 500 KJ/kg,advantageously less than 100 KJ/kg, method used: ASTM D 2015 and BS ENISO 1716), a high modulus of rupture (such as more than 10 MPa, forexample between 12 and 20 MPa, method of analysis: NBN EN 196-1), a highcompressive strength (more than 50 MPa, such as from 70 to 100 MPa,method of analysis: NBN EN 196-1), a high Young's modulus (more than 500MPa, such as between 8000 and 15000 MPa, method of analysis: NBN EN196-1), absence o swelling even for water absorption from 10% up to 30%depending of the porosity, etc.

[0084] Products of the invention can be used as insulating materials (aspanels, sheets, granules, etc), fire protection material, heatprotection material, chemical protection material, buildings material(such as bricks, concrete, etc.), for making molds, shaping, casting andmoldings products, tiles, roofing sheet, coating layers, inner layer,laminated products, metallic profile, aluminum profile, steel profile,metal band or plate, flexible membrane, polyethylene web. Polymer layer(polyurethane, latex, etc.), etc. Specific examples are: roofing sheet,insulation panels, coating surface material.

[0085] Wear resistant tile, high strength building elements, fire andheat resistant elements, adhesive material, sealants, slates, laminatedelements, joint compounds, refractory, mineral fibers, etc.

[0086] The invention relates also more precisely to a product made atleast partly or associated at least partly to a hardened composition ofthe invention, as disclosed here above. For example the product can be asupport provided with a coating layer with a thickness for example of 1to 10 mm, or even more.

[0087] The product can also have the form of a laminated product, aninner layer being made from a composition of the invention, said innerlayer having for example a thickness of 5 mm up to 100 mm, or even more.

[0088] According to an embodiment, the hardened layer covers at leastpartly a face of a support element. One or more faces of the support canbe provided with a hardened layer. The thickness of the layer isadvantageously lower than 10 mm, such as lower than 5 mm, such as 4 mm,3 mm, 2 mm, 1 mm, 500 μm, 250 μm, 100 μm, depending on the propertieswhich are required.

[0089] According to an advantageous embodiment, the hardened layercovers at least partly a face of a support comprising a core which canbe subjected to a water swelling. It has been observed that by coatingalready one face of a plate (which can be subjected to a water swelling)with a composition of the invention, it was possible to obtain afterhardening of the composition, a product which has a reduced swellingeven after being dipped in water for 72 hours at 20° C. Tests made oncommercial wood fiber composite material with a swelling of 37% afterbeing dipped in water for 72 hours at 20° C., have shown that byproviding one or more faces of the material with a thin hardened layerof the composition of the invention, it was possible to reduce theswelling to less than 10%, advantageously less than 6%, preferably lessthan 2%.

[0090] According to a specific embodiment, at least partly a face notcovered by a hardened layer of the invention is provided with a waterrepellent coating, advantageously silicon containing water repellentcoating, such as a fluoro silicon coating (fluoro silane, etc. such asfluorosilane marketed by 3M as water repellent agent, such as theproduct Scotchgard®)).

[0091] The thickness of the water repellent coating is advantageouslyless than 500 μm, such as less than 250 μm, preferably less than 150 μm,most preferably less than 100 μm, for example less than 50 μm, or evenlesser, such as less than 20 μm or even less than 10 μm.

[0092] According to a more specific embodiment, substantially all thefaces not covered with the hardened layer are provided with a waterrepellent coating.

[0093] According to an embodiment, the support has two substantiallyparallel faces (top and bottom faces or major faces, front and rearfaces) connected the one to the other by lateral faces, whereby saidlateral faces (bottom/top or front/rear faces) have a higher waterpermeability than the two substantially parallel faces. In saidembodiment, the lateral faces of the support are provided with a waterrepellent coating. The water repellent coating on said lateral facescovers also at least a portion of the front/rear faces along their edgesor at least a portion of the hardened layer adjacent to the edges ofsaid front and rear faces. The water repellent coating can be carriedout before and/or after providing the support with the hardened layer ofthe invention.

[0094] The Kit

[0095] The invention relates also to a kit for the preparation ofinorganic binder composition~according to the invention, said kitcomprising:

[0096] a container of bag containing a water insoluble calcium silicate,and

[0097] one or more containers or bags containing compounds for preparingan acid alumina-silica phosphate solution, the pH of said solutionmeasured at 20° C. being less than 1.5, advantageously less than 1,preferably less than 0.5.

[0098] The acid pH is advantageously obtained by using phosphoric acidor an acid mixture containing at least phosphoric acid. Preferably,substantially only phosphoric acid is used as mineral acid, mostpreferably as acid for lowering the pH of the solution to less than 2.The acid can be in a distinct container or can be used for thepreparation of an acid solution containing solubilized alumina-silicaphosphate, i.e. a ready to mix solution.

[0099] According to a preferred embodiment of the kit, the kitcomprises:

[0100] a container of bag containing a water insoluble calcium silicate,silicon containing fibers with a length of less than 1000 μm, andpossibly, but advantageously also silica flour with an average particlesize of less than 500 μm, and

[0101] one or more containers or bags containing compounds for preparingan acid alumina-silica phosphate solution or containing analumina-silica phosphate solution, the pH of said solution measured at20° C. being less than 1.5, advantageously less than 1, preferably lessthan 0.5, in which the silica is solubilized.

[0102] It has been observed that the premix of water insoluble calciumsilicate with silicon containing fibers with a length of less than 1000μm was in a form enabling an easily and quick mixing with an acidalumina-silica phosphate solution.

[0103] The water insoluble calcium silicate, the silicon containingfibers, the silica flour used in the kit has advantageously one or morecharacteristics as disclosed here above in the binder and compositionsof the invention.

[0104] The alumina-silica phosphate solution has advantageously a weightratio Al₂O₃/SiO₂ ranging from 0.3:1 and 10:1, preferably from 0.6:1 and6:1.

[0105] The kit advantageously further comprises a container with acomposition containing a water repellent agent, advantageously in theform of a solution, preferably a ready to use solution. Such acomposition is for example a water based solution or a solvent basedsolution containing a water repellent silane, preferably a fluorosilane.

[0106] The Process for the Preparation of a Binder/Composition of theInvention

[0107] A further subject matter of the invention is a process for thepreparation of a binder/composition according to the invention, in whichwater insoluble calcium silicate particles are mixed with an acidalumina-silica solution at a temperature lower than 50° C., said acidalumina-silica solution having a pH less than 2, advantageously lessthan 1.5, for example comprised between 0.1 and 1.5, preferablycomprised between 0.5 and 1.5.

[0108] The acid pH is advantageously obtained by using phosphoric acidor an acid mixture containing at least phosphoric acid. Preferably,substantially only phosphoric acid is used as mineral acid, mostpreferably as acid for lowering the pH of the solution to less than 2.

[0109] In the process of the invention, the alumina-silica phosphatesolution has advantageously a ratio Al₂O₃/SiO₂ ranging from 0.3:1 and10:1, preferably from 0.6:1 and 6:1.

[0110] In the process of the invention, a filler and/or a reinforcedmaterial is advantageously mixed with the calcium silicate particlesbefore being mixed with the acid alumina-silica phosphate solutionand/or a filler and/or a reinforced material is mixed to the mixturecalcium silicate/alumina-silica phosphate solution, before or during itshardening.

[0111] Preferably, the hardening of the binder is carried out at atemperature comprised between 0° C. and 50° C., possibly under pressure.

[0112] The binder of the invention is prepared by using an acidalumina-silica phosphate solution, said solution is advantageouslyprepared by reacting aluminum oxide powder (size advantageously lowerthan 50 μm, preferably lower than 30 μm, for example from 5 to 25 μm)with a purity of more than 95%, preferably more than 99%, silica powder(size advantageously lower than 50 μm, preferably lower than 30 μm, forexample from 10 to 25 μm) with a purity of more than 95%, preferably ofmore than 99%, and phosphoric acid as an aqueous phosphoric acid or inpresence of an aqueous medium. The phosphoric acid has preferably apurity of more than 95%, most preferably of more than 99%. Phosphoricacid is available in various concentration. Preferably, the phosphoricacid will be a phosphoric aqueous solution with a phosphoric acidconcentration of more than 75%, preferably of more than 85%. Preferably,the silica powder is first mixed with the phosphoric acid and then thealumina particles are added.

[0113] The acid alumina-silica phosphate solution contains possibly someother acids, such as organic acid, strong mineral acid, etc, however, inthis case, the content of such acid will preferably be less than 10% ofthe phosphoric acid content of the solution.

[0114] Instead of using aluminum oxide, it is possible to use aluminumphosphate, aluminum hydroxide, etc. However, aluminum oxide ispreferred.

[0115] Instead of using silica, preferably precipitated silicaparticles, it is possible to use waste material issuing from glassbottles.

[0116] Possibly the aqueous phosphoric acid solution contains othersolvents, such as alcohol, etc.

[0117] When a foamed product is desired, more water or solvent will beused for decreasing as much as possible the viscosity.

[0118] The acid alumina silica phosphate solution has advantageously apH lower than 2, preferably lower than 1.

[0119] It has been observed that when using silica particles for thepreparation of the acid alumina phosphate solution with a pH lower than2, most preferably lower than 1, the dissolution of alumina particleswas improved. The presence of solubilized SiO₂ in the acid solution wasalso improving the formation of the bonds when adding the waterinsoluble calcium silicate particles. Even, if some calcium silicateparticles are solubilized due to the low pH, some calcium silicateparticles remains insoluble, due for example to the increase of pH to avalue comprised between 3 and 6.

[0120] According to a specific embodiment, the process for thepreparation of a composition according to the invention is a process, inwhich a binding mixture is prepared by mixing water insoluble calciumsilicate particles with an acid alumina-silica phosphate solution at atemperature lower than 50° C., said acid alumina-silica phosphatesolution comprising solubilized SiO₂ and having a pH less than 2,advantageously less than 1.5, preferably comprised between 0.5 and 1.5,said alumina-silica phosphate solution having a weight ratio Al₂O₃/SiO₂ranging advantageously from 0.3:1 and 10:1, preferably from 0.6:1 and6:1, in which silicon containing fibers with a length of less than 1000μm are mixed with water insoluble calcium silicate particles, prior toor during the mixing of water insoluble silicate particles with an acidalumina-silica phosphate solution and/or in which silicon containingfibers with a length of less than 1000 μm are mixed with the bindingmixture before its complete hardening.

[0121] Preferably, the binding mixture is first prepared and then thesilicon containing fibers are added. Said addition is carried out whenthe binding mixture is still sufficiently liquid or pourable by gravity.Possibly before and/or during the addition of the fibers, water can beadded for controlling the viscosity. Possibly the silicon containingfibers are prewetted before being added to the binding mixture.

[0122] According to an advantageous embodiment, silica flour is added tothe water insoluble calcium silicate particles, prior to or during themixing of water insoluble silicate particles with an acid alumina-silicaphosphate solution and/or to the binding mixture before its completehardening, said addition being carried out prior, during or after theaddition of silicon containing fibers.

[0123] Preferably, the silicon containing fibers and the silica flourare premixed before being added to the acid alumina-silica phosphatesolution or to the binding mixture.

[0124] According to a possible embodiment, the insoluble calciumsilicate particles, the silicon containing fibers and the silica flourare premixed before being added to and mixed with the acidalumina-silica phosphate solution.

[0125] Advantageously, the weight ratio water insoluble calcium silicateparticles/solubilized SiO₂ present in the alumina-silica phosphatesolution is greater than 1, preferably greater than 1.5.

[0126] Preferably, the hardening of the binder/composition is carriedout at a temperature comprised between 0° C. and 50° C., such asadvantageously between 10 and 30° C.

[0127] The binder/composition is preferably hardened under pressure,such as under a pressure comprised between 2 10⁵ Pa and 100 10⁵ Pa, forexample 5 10⁵ Pa, 10⁶ Pa, 2 10⁶ Pa, etc.

[0128] The amount of calcium silicate added to the acid silica aluminaphosphate solution is advantageously such that the weight ratio calciumsilicate/SiO₂ present in the acid solution is comprised between 1 and 5,advantageously comprised between 1.5 and 3.5.

[0129] Preferably, the amount of calcium silicate added to the acidsilica alumina phosphate solution is such that the weight ratio calciumsilicate/SiO₂ present in the acid solution is greater than 2.

[0130] According to a preferred embodiment, the silica used for thepreparation of the acid silica alumina phosphate solution isprecipitated silica.

[0131] The acid alumina-silica solution before its mixing with insolublecalcium silicate particles has advantageously a pH of less than 2,preferably less than 1.5, for example comprised between 0.1 and 1.5,preferably comprised between 0.5 and 1.5. The acid pH is advantageouslyobtained by using phosphoric acid or an acid mixture containing at leastphosphoric acid. Preferably, substantially only phosphoric acid is usedas mineral acid, most preferably as acid for lowering the pH of thesolution to less than 2.

[0132] The calcium silicate particles are advantageously calcium metasilicate particles having a substantially acicular nature with alength/diameter ratio from 2/1 to 50/1, advantageously from 3/1 to 20/1.

[0133] The calcium meta silicate particles have preferably an averagelength from 10 μm to 10 mm, advantageously from 50 μm to 5 mm.

[0134] According to a preferred embodiment, the calcium silicateparticles act as cross-linking sites for alumina-silica phosphate bonds.It seems also that the presence of insoluble calcium silicate particlescatalyzes the formation of alumina-silica phosphate bonds.

[0135] In the process of the invention, the alumina-silica phosphatesolution has advantageously a weight ratio Al₂O₃/SiO₂ ranging from 0.3:1and 10:1, preferably from 0.6:1 and 6:1.

[0136] For example, the weight ratio calcium silicateparticles/alumina-silica phosphate solution is comprised between 0.1 and1.1, preferably from 0.3 and 0.9, most preferably between 0.4 and 0.7.

[0137] In the process of the invention, various filler and/or areinforced material can be mixed with the calcium silicate particlesbefore being mixed with the acid alumina-silica phosphate solution,and/or a filler and/or a reinforced material is mixed to the mixturecalcium silicate/alumina-silica phosphate solution, before its or duringits hardening.

[0138] Examples of fillers or reinforced materials which can be mixedwith the binder before its preparation, during its preparation, beforeits hardening or during its hardening are:

[0139] waste materials, such as finely divided waste material, forexample fuel ashes, fly ashes, buildings waste materials, etc.

[0140] flake-like materials such as mica, etc.,

[0141] silica sand, silica flour,

[0142] coloring agents or materials, such as inorganic coloring agents,pigments, etc.

[0143] cellulose and/or protein base fibers, such as natural fibers,flax, chip, straw, hemp, wool fibers, etc.

[0144] synthetic fibers, such as organic synthetic fibers, inorganicsynthetic fibers, such as polyesters, polypropylene, glass and ceramicfibers, etc.

[0145] natural and synthetic organic base waste materials, such as sawdust, rice husk, straw and recycled organic waste,

[0146] natural fibers of mineral origin,

[0147] natural material, possibly treated (for example heat treated),such as perlite, vermiculite, etc.

[0148] etc.

[0149] Additives can be added to the binder/composition before itspreparation, during its preparation, before its hardening or during itshardening, such additives are for example:

[0150] foaming agents, such as water peroxide, organic peroxide, etc.

[0151] viscosity regulating agent, such as superplasticizer

[0152] material for improving the impermeability or the water repulsionsuch as lignosulfonates and silica fume

[0153] etc.

[0154] Possibly, additives or fillers can be added during or after thehardening, for example for making a top coat.

[0155] The binder/composition of the invention is prepared by using anacid alumina-silica phosphate solution, said solution is advantageouslyprepared by reacting aluminum oxide powder (size advantageously lowerthan 50 μm, preferably lower than 30 μm, for example from 5 to 25 μm)with a purity of more than 95%, preferably more than 99%, silica powder(size advantageously lower than 50 μm, preferably lower than 30 μm, forexample from 10 to 25 μm) with a purity of more than 95%, preferably ofmore than 99%, and phosphoric acid as an aqueous phosphoric acid or inpresence of an aqueous medium. The phosphoric acid has preferably apurity of more than 95%, most preferably of more than 99%.

[0156] Phosphoric acid is available in various concentration.Preferably, the phosphoric acid will be a phosphoric aqueous solutionwith a phosphoric acid concentration of more than 75%, preferably ofmore than 85%. Preferably, the silica powder is first mixed with thephosphoric acid and then the alumina particles are added.

[0157] The acid alumina-silica phosphate solution contains possibly someother acids, such as organic acid, strong mineral acid, etc, however, inthis case, the content of such acid will preferably be less than 10% ofthe phosphoric acid content of the solution.

[0158] Instead of using aluminum oxide, it is possible to use aluminumphosphate, aluminum hydroxide, etc. However, aluminum oxide ispreferred.

[0159] Instead of using silica, preferably precipitated silicaparticles, it is possible to use waste material issuing from glassbottles.

[0160] Possibly the aqueous phosphoric acid solution contains othersolvents, such as alcohol, etc.

[0161] When a foamed product is desired, more water or solvent will beused for decreasing as much as possible the viscosity. It is alsopossible to obtain a foaming product by applying the acid composition ona base containing support or on an alkaline support.

[0162] The acid alumina silica phosphate solution has advantageously apH lower than 2, preferably lower than 1.

[0163] It has been observed that when using silica particles for thepreparation of the acid alumina phosphate solution with a pH lower than2, most preferably lower than 1, the dissolution of alumina particleswas improved. The presence of solubilized SiO₂ in the acid solution wasalso improving the formation of the bonds when adding the waterinsoluble calcium silicate particles. Even, if some calcium silicateparticles are solubilized due to the low pH, some calcium silicateparticles remains insoluble, due for example to the increase of pH to avalue comprised between 3 and 6.

EXAMPLES

[0164] Details and characteristics of the invention will appear from thedescription of the following examples.

[0165] In said examples, the following products have been used:

[0166] WATER: water with a low calcium/magnesium content (less than 100ppm)

[0167] SiO₂: precipitated SiO₂ particles with an average size of 10-15μm—purity of 99%

[0168] Al₂O₃: powder with an average particle size of 10-15 μm—purity of99%

[0169] Phosphoric acid: aqueous solution containing 90% phosphoric acid

[0170] Calcium silicate: calcium meta silicate powder, water insoluble,acicular nature, length of 1 mm, diameter 100 μm.

[0171] Rice Husk fibers (RHF1): dried natural fibers (water content lessthan 2%) with an average (in weight) length of about 100 μm.

[0172] Rice Husk fibers (RHF2): dried natural fibers (water content lessthan 2%) with an average (in weight) length of about 200 μm.

[0173] Rice bran ceramic fiber (RBCF1): defatted bran mixed withphenolic resin, shaped in filament, dried and carbonized and burnt undernitrogen atmosphere at 800° C., the fibers having a length of about 100μm.

[0174] Rice bran ceramic particles (RBC): defatted bran mixed withphenolic resin, powdered, dried and carbonized and burnt under nitrogenatmosphere at 800° C., the powder having an average particle size(average in weight) of about 50 μm.

[0175] Crystallized alumina silicate (CAS): not reactive with thephosphate solution, the particles having an average particle size of 50μm (average in weight).

[0176] Silica Flour (SF): average (in weight) particle size of about 30μm

[0177] Silica fume (Sf): average (in weight) particle size 50 μm.

[0178] Glass fiber (GF): glass fibres with a length of 50 μm to 250 μm,which have been treated with a water repellent agent (fluoro silane)

Examples of Binders

[0179] The binders have been prepared by adding SiO₂ particles tophosphoric acid. After dissolution of the SiO₂ particles, Al₂O₃particles were added. An acid alumina silica phosphate aqueous solutionwas so prepared. The pH of said acid solution was then measured at 20°C. Possibly some water was added.

[0180] To said acid solution, calcium silicate particles was added. 5 to10 minutes after the addition of calcium silicate particles, the bindercan be hardened. Said hardening can be made at room temperature. Inorder to control the viscosity of the mixture, water can be added.

[0181] The following table gives the composition of the bindersprepared. Binder 1 2 3 4 5 6 7 8 9 10 SiO₂ (g) 35 16 21 13.6 46.2 60 182130.8 97.2 233 Al₂O₃ 24 23 13 50.8 30.8 60 136.5 21.8 58.1 46.6 (g)Phosphoric 141 141 167 123 135.6 180 182 87.4 184.7 350.4 acid (g) Molar0.43 0.2 0.2 0.19 0.59 0.58 1.73 2.62 0.92 1.15 Ratio SiO₂/P₂O₅ Of thesolution Calcium 120 100 150 60 100 150 200 140 240 310 silicate (g)Water (ml) 80 40 25 60 118 21 71 65 pH of the 0.5 0.5 0.5 0.5 0.5 0.50.5 0.5 0.5 0.5 acid solution pH of the 1 0.5 1 0.5 0.5 1.5 1 1 1.5 1.5solution after addition of the calcium silicate Appearance LS LS S-D S-DP LS LS S-D P P of the mixture after the addition of the calciumsilicate (LS, S-D, P)*

[0182] In the process of the invention, the amount of calcium silicateadded to the acid silica alumina phosphate solution is such that theweight ratio calcium silicate/SiO₂ present in the acid solution isadvantageously greater than 1, preferably greater than 1.5, mostpreferably greater than 2, for example comprised between 1 and 5,advantageously comprised between 1.5 and 3.5.

[0183] The binders 3 to 5 and 8 to 10, after their preparation, aremixed with water so as to have a more liquid appearance, whereby theaddition of fibers and other particles is more adequate.

Examples of Compositions of the Invention

[0184] The binder n°2 which is liquid after its preparation was mixedwith various additives and/or filler.

[0185] The following tables gives the different additives and fillersused, expressed in part by weight, the binder being expressed as drymatter (without water). TABLE 1 Product n° 1 2 3 4 5 6 7 8 Binder (dry 11 1 1 1 1 1 1 matter, part by weight) RHF1 0.1 0.1 0.5 RHF2 0.1 RBCF10.2 0.4 0.4 0.4 RBC 0.3 CAS 0.2 SF 0.02 0.02 0.05 0.05 0.1 0.1 0.1 0.1Sf 0.1 0.2 0.2 GF 0.5 1

[0186] TABLE 2 Product n° 9 10 11 12 13 14 Binder (part 1 1 1 1 1 1 byvolume) Additive H₂O₂ Silica Aluminum Super Ligno- Quartz (Part by 0.13Fume powder Plasticizer Sulfonate 0.54 volume) 0.42 0.12 0.15 0.13Filler Vermiculite Straw Fly ash Chip Flax Silica (part by 0.33 3 parts0.52 1.22 Fiber Flour volume) 0.75 0.25 Appearance Foam, Low Foam LowLow Heavy of the product low density density Low density density densitydensity

[0187] For the preparation of said compositions, water can be added forcontrolling the viscosity of the composition, said viscosity beingpreferably maintained as low as possible during the mixing step.

[0188] To the compositions of Table 1, one or more further additives orfillers can be added.

[0189] The following table gives possible additives and fillers whichcan be added to the compositions of the table 1. Said addition iscarried out when the composition is sufficient liquid. Possibly somewater is added before the addition and/or during the addition of saidadditives and fillers. Examples of possible additive and filler added toone volume of a composition with a solid content of 25% and 50% byweight Additive Silica Aluminum Super Ligno- H₂O₂ Fume powderPlasticizer Sulfonate Quartz (Part by 0.13 0.42 0.12 0.15 0.13 0.54volume) Filler Vermiculite Straw Fly ash Chip Flax Silica (part by 0.333 parts 0.52 1.22 Fiber Flower volume) 0.75 0.25 Appearance Foam, LowFoam Low Low Heavy of the product low density density Low densitydensity density density

[0190] The composition comprising one or more inert fillers arepreferably prepared by premixing at least partly the inert fillers withthe calcium silicate, before using said calcium silicate for thepreparation of the binder. The premix was thus mixed with the acidsilica alumina phosphate solution.

Examples of Coating Operation

[0191] A wood board with a thickness of 20 mm has been cut in sampleswith a size of 200 mm×200 mm. One sample was used as control sample.Said control sample was dipped in water at 20° C. for 72 hours. Thewater absorption of the control sample was 46% (i.e. the weight of thewood board was increased by 46% due to the dipping in water, withrespect to the weight of the dry board before its dipping—dry meaning awater content of less than 10% by weight in the board), while theswelling of the product was 37% (i.e. the volume of the sample wasincreased by 37% due to the dipping with respect to the volume of thedry board—dry meaning a water content of less than 10% by weight),

[0192] The samples have been submitted respectively to the followingtreatment.

[0193] Sample 1

[0194] Composition 7 of Table 1 has been used just after its preparationfor coating the upper face of sample. The coating after drying had athickness of 2 mm.

[0195] After its complete curing, the sample was dipped in water (20°C.) for 72 hours. The water absorption was about 25% with a swelling ofabout 8%.

[0196] Sample 2

[0197] Sample 2 was prepared as disclosed for sample 1, except thatafter coating the front face, the rear face was also coated with a mmthick coating (composition 7 of Table 1).

[0198] After its complete curing of the two coating layer, the samplewas dipped in water (20° C.) for 72 hours. The water absorption wasabout 20% with a swelling of about 6%.

[0199] Sample 3

[0200] Sample 3 was prepared as disclosed for example 2, except thatthereafter the four lateral faces of the sample were also provided witha coating layer (composition 7), said layer having a thickness of about1-2 mm.

[0201] After complete curing or hardening of the coating layer, thesample was dipped in water (20° C.) for 72 hours. The water absorptionwas about 14% with a swelling of about 2%.

[0202] Sample 4

[0203] Sample 4 was prepared as disclosed in example 2, except that thelateral faces were treated with a water repellent agent (scotchgard™3M).

[0204] After the complete curing of the two coating layer and of thewater repellent agent, the sample was dipped in water (20° C.) for 72hours. The water absorption was about 14% with a swelling of about 0%.

[0205] Sample 5

[0206] Sample 4 was prepared as disclosed in example 1, except that thelateral faces were treated with a water repellent agent (scotchgard™3M).

[0207] After the complete curing of the two coating layer and of thewater repellent agent, the sample was dipped in water (20° C.) for 72hours. The water absorption was about 15% with a swelling of about 0-2%.

[0208] Sample 6

[0209] Sample 6 was prepared as disclosed in example 2, except thatbefore the coating of the rear and front faces with the composition 7 ofTable 1, the lateral faces as well as the edges of the front and rearfaces were treated with a water repellent agent.

[0210] After the complete curing of the two coating layer and of thewater repellent agent, the sample was dipped in water (20° C.) for 72hours. The water absorption was about 14% with a swelling of about 0-2%.

[0211] Sample 7

[0212] Sample 7 was prepared as disclosed for sample 3, except thatthereafter the hardened layer was further coated with a water repellentagent (scotchgard).

[0213] After the complete curing of the two coating layer and of thewater repellent agent, the sample was dipped in water (20° C.) for 72hours. The water absorption was about 15% with a swelling of about 0-2%.

[0214] Sample 8

[0215] Sample 8 was prepared as disclosed for sample 3, except thatbefore applying the hardened layer of composition 7, all the faces ofthe sample were coated with a water repellent agent (scotchgard).

[0216] After the complete curing of the two coating layer and of thewater repellent agent, the sample was dipped in water (20° C.) for 72hours. The water absorption was about 15% with a swelling of about 0-2%.

[0217] The water absorption and swelling tests was repeated withoriented strand board. The conclusions of the samples 1 to 8 weremaintained.

[0218] The composition 6 was applied on a face of a polyethylene web of200 g/m². After hardening of the composition, a flexible film layer wasobtained.

[0219] The composition 8 was poured so as to produce samples for beingtested according to the standards BS EN ISO 1716 and ASTMD2015. Themaximum amount of heat that the sample can release under highlyidealized conditions was determined in an oxygen bomb calorimeter usingadiabatic and isothermal methods. This test determines the maximum totalheat release of the material after complete combustion, i.e. thedifference between the gross heat of combustion and the residual heatafter 2 hours of combustion. A gross heat of combustion of 85 KJ/Kg wasdetermined, meaning that the product is considered as an extremely noncombustible materials (M0).

[0220] Mechanical tests were also performed on the sample according tothe NBN EN 196-1 standards. It was determined that the product had thefollowing properties modulus of rupture 15.5 Mpa, compressive strength30-40 Mpa, young's modulus 2200-4500 Mpa.

[0221] The water capillary porosity was of about 13-14% (ASTM C948-81).

What I claim is:
 1. An inorganic binder having calcium silicate siteswhich are connected the one with the other by alumina-silica phosphatebonds, the calcium silicate sites acting as cross-linking sites for thealumina-silica phosphate bonds with a weight ratio Al₂O₃/SiO₂ rangingfrom 0.3:1 and 10:1.
 2. The binder of claim 1, in which the calciumsilicate sites act as cross-linking sites for the alumina-silicaphosphate bonds with a weight ratio Al₂O₃/SiO₂ ranging from 0.6:1 and6:1.
 3. The binder of claim 1, in which substantially all calciumsilicate sites are bound the one to the other by alumina-silicaphosphate bonds.
 4. The binder of claim 1, in which the weight ratiocalcium silicate site/SiO₂ present in the alumina-silica phosphate bondsis greater than
 1. 5. The binder of claim 1, in which the weight ratiocalcium silicate site/SiO₂ present in the alumina-silica phosphate bondsis greater than 1.5.
 6. The binder of claim 1, in which the calciumsilicate sites are calcium meta silicate sites having a substantiallyacicular nature with a length/diameter ratio from 2/1 to 50/1.
 7. Thebinder of claim 1, in which the calcium silicate sites are calcium metasilicate sites having a substantially acicular nature with alength/diameter ratio from 3/1 to 20/1.
 8. The binder of claim 1, inwhich the calcium silicate sites are calcium meta silicate sites havinga substantially acicular nature with a length/diameter ratio from 2/1 to50/1, the calcium meta silicate sites having an average length from 10μm to 10 mm.
 9. The binder of claim 1, in which the calcium silicatesites are calcium meta silicate sites having a substantially acicularnature with a length/diameter ratio from 2/1 to 50/1, the calcium metasilicate sites having an average length from 50 μm to 5 mm.
 10. Thebinder of anyone of the claims 1, in which the weight ratio calciumsilicate sites/alumina-silica phosphate bonds is comprised between 0.1and 1.1.
 11. The binder of anyone of the claims 1, in which the weightratio calcium silicate sites/alumina-silica phosphate bonds is comprisedbetween 0.3 and 0.9.
 12. The binder of anyone of the claims 1, in whichthe weight ratio calcium silicate sites/alumina-silica phosphate bondsis comprised between 0.4 and 0.7.
 13. A composition comprising at least:an inorganic binder having calcium silicate sites which are connectedthe one with the other by alumina-silica phosphate bonds, the calciumsilicate sites acting as cross-linking sites for the alumina-silicaphosphate bonds with a weight ratio Al₂O₃/SiO₂ ranging from 0.3:1 and10:1, and a filler.
 14. The composition of claim 13, in which thecalcium silicate sites of the inorganic binder act as cross-linkingsites for the alumina-silica phosphate bonds with a weight ratioAl₂O₃/SiO₂ ranging from 0.6:1 and 6:1.
 15. The composition of claim 13,in which substantially all calcium silicate sites of the inorganicbinder are bound the one to the other by alumina-silica phosphate bonds.16. The composition of claim 13, in which the weight ratio calciumsilicate site/SiO₂ present in the alumina-silica phosphate bonds of theinorganic binder is greater than
 1. 17. The composition of claim 13, inwhich the weight ratio calcium silicate site/SiO₂ present in thealumina-silica phosphate bonds of the inorganic binder is greater than1.5.
 18. The composition of claim 13, in which the calcium silicatesites of the inorganic binder are calcium meta silicate sites having asubstantially acicular nature with a length/diameter ratio from 2/1 to50/1.
 19. The composition of claim 13, in which the calcium silicatesites of the inorganic binder are calcium meta silicate sites having asubstantially acicular nature with a length/diameter ratio from 3/1 to20/1.
 20. The composition of claim 13, in which the calcium silicatesites of the inorganic binder are calcium meta silicate sites having asubstantially acicular nature with a length/diameter ratio from 2/1 to50/1, the calcium meta silicate sites having an average length from 10μm to 10 mm.
 21. The composition of claim 13, in which the calciumsilicate sites of the inorganic binder are calcium meta silicate siteshaving a substantially acicular nature with a length/diameter ratio from2/1 to 50/1, the calcium meta silicate sites having an average lengthfrom 50 μm to 5 mm.
 22. The composition of claim 13, in which the weightratio calcium silicate sites/alumina-silica phosphate bonds of theinorganic binder is comprised between 0.1 and 1.1.
 23. The compositionof claim 13, in which the weight ratio calcium silicatesites/alumina-silica phosphate bonds of the inorganic binder iscomprised between 0.3 and 0.9.
 24. The composition of claim 13, in whichthe weight ratio calcium silicate sites/alumina-silica phosphate bondsof the inorganic binder is comprised between 0.4 and 0.7.
 25. Thecomposition-of claim 13, in which the filler is a silicon containingfiller.
 26. The composition of claim 13, in which the filler comprisessilicon containing fibers with a length of less than 1000 μm.
 27. Thecomposition of claim 13, which comprises silicon containing fibers witha length of less than 1000 μm, the weight content of silicon containingfibers with a length of less than 1000 μm in the composition after itshardening and after removal of the possible free water being of at least0.5%.
 28. A composition comprising at least: an inorganic binder havingcalcium silicate sites which are connected the one with the other byalumina-silica phosphate bonds, the calcium silicate sites acting ascross-linking sites for the alumina-silica phosphate bonds with a weightratio Al₂O₃/SiO₂ ranging from 0.3:1 and 10:1, and silicon containingfibers with a length of less than 100 μm, the weight content of siliconcontaining fibers with a length of less than 1000 μm in the compositionafter its hardening and after removal of the possible free water beingof at least 0.5%.
 29. The composition of claim 28, which comprisessilicon containing fibers with an average (in weight) length of lessthan 500 μm, the weight content of silicon containing fibers with anaverage length of less than 500 μm in the composition after itshardening and after removal of the possible free water being of at least0.5%.
 30. The composition of claim 28, which comprises siliconcontaining fibers with an average (in weight) length of more than 10 μm.31. The composition of claim 28, which comprises silicon containingfibers with an average (in weight) length of more than 20 μm.
 32. Thecomposition of claim 28, which comprises silicon containing fibers withan average (in weight) length comprised between 25 μm and 300 μm. 33.The composition of claim 28, which comprises silicon containing fiberswith an average (in weight) length between 50 μm and 250 μm.
 34. Thecomposition of claim 28, in which the silicon containing fibers with alength of less than 1000 μm are substantially not reactive with thebinder.
 35. The composition of claim 28, in which the silicon containingfibers with a length of less than 500 μm are substantially not reactivewith the binder.
 36. The composition of claim 28, in which the siliconcontaining fibers with a length of less than 1000 μm are not reactivewith the binder.
 37. The composition of claim 28, in which the siliconcontaining fibers with a length of less than 500 μm are not reactivewith the binder.
 38. The composition of claim 28, which, after hardeningand removal of free water, comprises from 1% up to 85% by weight,silicon containing fibers with a length of less than 1000 μm, which aresubstantially not reactive with the binder.
 39. The composition of claim28, which, after hardening and removal of free water, comprises from 1%up to 85% by weight, silicon containing fibers with a length of lessthan 1000 μm, which are not reactive with the binder.
 40. Thecomposition of claim 28, which, after hardening and removal of freewater, comprises from 2% up to 75% by weight, silicon containing fiberswith a length of less than 1000 μm, which are not reactive with thebinder.
 41. The composition of claim 28, which, after hardening andremoval of free water, comprises from 1% up to 85% by weight, siliconcontaining fibers with a length of less than 500 μm, which are notreactive with the binder.
 42. The composition of claim 28, which, afterhardening and removal of free water, comprises from 2% up to 75% byweight, silicon containing fibers with a length of less than 500 μm,which are not reactive with the binder.
 43. The composition of claim 28,which, after hardening and removal of free water, comprises from 20% upto 65% by weight silicon containing fibers with a length of less than1000 μm which are substantially not reactive with the binder.
 44. Thecomposition of claim 28, which, after hardening and removal of freewater, comprises from 30% up to 60% by weight silicon containing fiberswith a length of less than 500 μm, which are not reactive with thebinder.
 45. The composition of claim 28, which further comprises silicaflour with a particle size of less than 500, μm, the weight content ofsilica flour in the composition after its hardening and after removal ofthe possible free water being of at least 0.5%.
 45. The composition ofclaim 28, which further comprises silica flour with a particle size ofless comprised between 2 and 400 μm, the weight content of silica flourin the composition after its hardening and after removal of the possiblefree water being of at least 0.5%.
 46. The composition of claim 28,which further comprises silica flour with an average (in weight)particle size comprised between 2 and 100 μm, the weight content ofsilica flour in the composition after its hardening and after removal ofthe possible free water being comprised between 1 and 10%.
 47. Thecomposition of claim 28, which further comprises silica flour with anaverage (in weight) particle size comprised between 2 and 100 μm, theweight content of silica flour in the composition after its hardeningand after removal of the possible free water being comprised between 2and 8%.
 48. The composition of claim 28, which further comprises silicaflour with an average (in weight) particle size comprised between 5 and60 μm, the weight content of silica flour in the composition after itshardening and after removal of the possible free water being comprisedbetween 2 and 8%.
 49. The composition of claim 28, which furthercomprises silica flour with an average (in weight) particle sizecomprised between 10 and 50 μm the weight content of silica flour in thecomposition after its hardening and after removal of the possible freewater being comprised between 2 and 8%.
 50. The composition of claim 28,which further comprises crystallized alumina silicate particles whichare substantially not reactive with the binder and which have an average(in weight) particle size comprised between 5 and 100 μm, the weightcontent of non reactive crystallized alumina silicate in the compositionafter its hardening and after removal of the possible free water beingcomprised between 1 and 10%.
 51. The composition of claim 28, whichfurther comprises crystallized alumina silicate particles which aresubstantially not reactive with the binder and which have an average (inweight) particle size comprised between 5 and 100 μm, the weight contentof non reactive crystallized alumina silicate in the composition afterits hardening and after removal of the possible free water beingcomprised between 2 and 8%.
 52. The composition of claim 28, in whichthe calcium silicate sites of the inorganic binder act as cross-linkingsites for the alumina-silica phosphate bonds with a weight ratioAl₂O₃/SiO₂ ranging from 0.6:1 and 6:1.
 53. The composition of claim 28,in which the weight ratio calcium silicate site/SiO₂ present in thealumina-silica phosphate bonds of the inorganic binder is greaterthan
 1. 54. The composition of claim 28, in which the weight ratiocalcium silicate site/SiO₂ present in the alumina-silica phosphate bondsof the inorganic binder is greater than 1.5.
 55. The composition ofclaim 28, in which the calcium silicate sites of the inorganic binderare calcium meta silicate sites having a substantially acicular naturewith a length/diameter ratio from 2/1 to 50/1.
 56. The composition ofclaim 28, in which the calcium silicate sites of the inorganic binderare calcium meta silicate sites having a substantially acicular naturewith a length/diameter ratio from 3/1 to 20/1.
 57. The composition ofclaim 55, in which the calcium meta silicate sites has an average lengthfrom 10 μm to 10 mm.
 58. The composition of claim 56, in which thecalcium meta silicate sites has an average length from 50 μm to 5 mm.59. The composition of claim 28, in which the weight ratio calciumsilicate sites/alumina-silica phosphate bonds of the inorganic binder iscomprised between 0.1 and 1.1.
 60. The composition of claim 28, in whichthe weight ratio calcium silicate sites/alumina-silica phosphate bondsof the inorganic binder is comprised between 0.3 and 0.9.
 61. Thecomposition of claim 28, in which the weight ratio calcium silicatesites/alumina-silica phosphate bonds of the inorganic binder iscomprised between 0.4 and 0.7.
 62. A product comprising at least ahardened layer comprising an inorganic binder having calcium silicatesites which are connected the one with the other by alumina-silicaphosphate bonds, the calcium silicate sites acting as cross-linkingsites for the alumina-silica phosphate bonds with a weight ratioAl₂O₃/SiO₂ ranging from 0.3:1 and 10:1.
 63. The product of claim 62, inwhich the layer further comprises at least a filler.
 64. The product ofclaim 62, in which the hardened layer covers at least partly a face of asupport element.
 65. The product of claim 62, in which the hardenedlayer covers at least partly a face of a support comprising a core whichcan be subjected to a water swelling, and in which at least partly aface not covered by hardened layer is provided with a water repellentcoating.
 66. The product of claim 65, in which the water repellentcoating is a silicon containing water repellent coating.
 67. The productof claim 66, in which the water repellent coating is a fluoro siliconcoating.
 68. The product of claim 62, in which the hardened layer coversat least partly a face of a support comprising a core which can besubjected to a water swelling, and in which the faces not with ahardened layer are provided with a water repellent coating.
 69. Theproduct of claim 68, in which the water repellent coating is a siliconcontaining water repellent coating.
 70. The product of claim 62, inwhich the hardened layer covers at least partly a face of a supportcomprising a core which can be subjected to a water swelling, said facebeing provided with a water repellent coating.
 71. The product of claim62, in which the hardened layer comprises at least: an inorganic binderhaving calcium silicate sites which are connected the one with the otherby alumina-silica phosphate bonds, the calcium silicate sites acting ascross-linking sites for the alumina-silica phosphate bonds with a weightratio Al₂O₃/SiO₂ ranging from 0.3:1 and 10:1, and silicon containingfibers with a length of less than 1000 μm, the weight content of siliconcontaining fibers with a length of less than 1000 μm in the compositionafter its hardening and after removal of the possible free water beingof at least 0.5%.
 72. The product of claim 71, which comprises siliconcontaining fibers with an average (in weight) length of less than 500μm, the weight content of silicon containing fibers with an averagelength of less than 500 μm in the composition after its hardening andafter removal of the possible free water being of at least 0.5%.
 73. Theproduct of claim 62, in which the hardened layer comprises siliconcontaining fibers with an average (in weight) length of more than 10 μm.74. The product of claim 62, in which the hardened layer comprisessilicon containing fibers with an average (in weight) length of morethan 20 μm.
 75. The product of claim 62, in which the hardened layercomprises silicon containing fibers with an average (in weight) lengthcomprised between 25 μm and 300 μm.
 76. The product of claim 62, inwhich the hardened layer comprises silicon containing fibers with anaverage (in weight) length between 50 μm and 250 μm.
 77. The product ofclaim 62, in which the hardened layer comprises silicon containingfibers with a length of less than 1000 μm which are substantially notreactive with the binder.
 78. The product of claim 62, in which thehardened layer comprises silicon containing fibers with a length of lessthan 500 μm which are substantially not reactive with the binder. 79.The product of claim 62, in which the hardened layer comprises siliconcontaining fibers with a length of less than 1000 μm, which are notreactive with the binder.
 80. The product of claim 62, in which thehardened layer comprises silicon containing fibers with a length of lessthan 500 μm which are not reactive with the binder.
 81. The product ofclaim 62, in which, after hardening and removal of free water, thehardened layer comprises from 1% up to 85% by weight, silicon containingfibers with a length of less than 1000 μm, which are substantially notreactive with the binder.
 82. The product of claim 62, in which, afterhardening and removal of free water, the hardened layer comprises from1% up to 85% by weight, silicon containing fibers with a length of lessthan 1000 μm, which are not reactive with the binder.
 83. The product ofclaim 62, in which, after hardening and removal of free water, thehardened layer comprises from 2% up to 75% by weight, silicon containingfibers with a length of less than 1000 μm, which are not reactive withthe binder.
 84. The product of claim 62, in which, after hardening andremoval of free water, the hardened layer comprises from 1% up to 85% byweight, silicon containing fibers with a length of less than 500 μm,which are not reactive with the binder.
 85. The product of claim 62, inwhich, after hardening and removal of free water, the hardened layercomprises from 2% up to 75% by weight, silicon containing fibers with alength of less than 500 μm, which are not reactive with the binder. 86.The product of claim 62, in which, after hardening and removal of freewater, the hardened layer comprises from 20% up to 65% by weight siliconcontaining fibers with a length of less than 1000 μm which aresubstantially not reactive with the binder.
 87. The product of claim 62,in which, after hardening and removal of free water, the hardened layercomprises from 30% up to 60% by weight silicon containing fibers with alength of less than 500 μm, which are not reactive with the binder. 88.The product of claim 62, in which the hardened layer further comprisessilica flour with a particle size of less than 500 μm, the weightcontent of silica flour in the composition after its hardening and afterremoval of the possible free water being of at least 0.5%.
 89. Theproduct of claim 62, in which the hardened layer further comprisessilica flour with a particle size of less comprised between 2 and 400μm, the weight content of silica flour in the composition after itshardening and after removal of the possible free water being of at least0.5%.
 90. The product of claim 62, in which the hardened layer furthercomprises silica flour with an average (in weight) particle sizecomprised between 2 and 100 μm, the weight content of silica flour inthe composition after its hardening and after removal of the possiblefree water being comprised between 1 and 10%.
 91. The product of claim62, in which the hardened layer further comprises silica flour with anaverage (in weight) particle size comprised between 2 and 100 μm, theweight content of silica flour in the composition after its hardeningand after removal of the possible free water being comprised between 2and 8%.
 92. The product of claim 62, in which the hardened layer furthercomprises silica flour with an average (in weight) particle sizecomprised between 5 and 60 μm, the weight content of silica flour in thecomposition after its hardening and after removal of the possible freewater being comprised between 2 and 8%.
 93. The product of claim 62, inwhich the hardened layer further comprises silica flour with an average(in weight) particle size comprised between 10 and 50 μm the weightcontent of silica flour in the composition after its hardening and afterremoval of the possible free water being comprised between 2 and 8%. 94.The product of claim 62, in which the hardened layer further comprisescrystallized alumina silicate particles which are substantially notreactive with the binder and which have an average (in weight) particlesize comprised between 5 and 100 μm, the weight content of non reactivecrystallized alumina silicate in the composition after its hardening andafter removal of the possible free water being comprised between 1 and10%.
 95. The product of claim 62, in which the hardened layer furthercomprises crystallized alumina silicate particles which aresubstantially not reactive with the binder and which have an average (inweight) particle size comprised between 5 and 100 μm, the weight contentof non reactive crystallized alumina silicate in the composition afterits hardening and after removal of the possible free water beingcomprised between 2 and 8%.
 96. The product of claim 62, in which thecalcium silicate sites of the inorganic binder act as cross-linkingsites for the alumina-silica phosphate bonds with a weight ratioAl₂O₃/SiO₂ ranging from 0.6:1 and 6:1.
 97. The product of claim 62, inwhich the weight ratio calcium silicate site/SiO₂ present in thealumina-silica phosphate bonds of the inorganic binder is greaterthan
 1. 98. The product of claim 62, in which the weight ratio calciumsilicate site/SiO₂ present in the alumina-silica phosphate bonds of theinorganic binder is greater than 1.5.
 99. The product of claim 62, inwhich the calcium silicate sites of the inorganic binder are calciummeta silicate sites having a substantially acicular nature with alength/diameter ratio from 2/1 to 50/1.
 100. The product of claim 62, inwhich the calcium silicate sites of the inorganic binder are calciummeta silicate sites having a substantially acicular nature with alength/diameter ratio from 3/1 to 20/1.
 101. The product of claim 99, inwhich the calcium meta silicate sites has an average length from 10 μmto 10 mm.
 102. The product of claim 100, in which the calcium metasilicate sites has an average length from 50 μm to 5 mm.
 103. Theproduct of claim 62, in which the weight ratio calcium silicatesites/alumina-silica phosphate bonds of the inorganic binder iscomprised between 0.1 and 1.1.
 104. The product of claim 62, in whichthe weight ratio calcium silicate sites/alumina-silica phosphate bondsof the inorganic binder is comprised between 0.3 and 0.9.
 105. Theproduct of claim 62, in which the weight ratio calcium silicatesites/alumina-silica phosphate bonds of the inorganic binder iscomprised between 0.4 and 0.7.
 106. A kit for the preparation of aninorganic binder having calcium silicate sites which are connected theone with the other by alumina-silica phosphate bonds, the calciumsilicate sites acting as cross-linking sites for the alumina-silicaphosphate bonds with a weight ratio Al₂O₃/SiO₂ ranging from 0.3:1 and10:1, said kit comprising: a container containing a water insolublecalcium silicate, and at least one container containing at least onecompound suitable for preparing an acid alumina-silica phosphatesolution, in which the silica is solubilized.
 107. The kit of claim 106,which comprises at least a container containing at least one acidsuitable for preparing an acid alumina-silica phosphate solution with apH lower than 1.5 measured at 20° C.
 108. The kit of claim 106, whichcomprises at least a container containing at least one acid suitable forpreparing an acid alumina-silica phosphate solution with a pH lower than1 measured at 20° C.
 109. The kit of claim 106, in which the containercontaining a water insoluble calcium silicate further contains siliconcontaining fibers with a length of less than 1000 μm.
 110. The kit ofclaim 106, in which the container containing a water insoluble calciumsilicate further contains silica flour with an average particle size ofless than 500 μm.
 111. A kit for the preparation of an inorganic binderhaving calcium silicate sites which are connected the one with the otherby alumina-silica phosphate bonds, the calcium silicate sites acting ascross-linking sites for the alumina-silica phosphate bonds with a weightratio Al₂O₃/SiO₂ ranging from 0.3:1 and 10:1, said kit comprising: acontainer containing a water insoluble calcium silicate, and at leastone container containing at least an acid alumina-silica phosphatesolution, in which the silica is solubilized.
 112. The kit of claim 111,which comprises at least one container containing at least an acidalumina-silica phosphate solution with a pH lower than 1.5 measured at20° C.
 113. The kit of claim 111, which comprises at least one containercontaining at least an acid alumina-silica phosphate solution with a pHlower than 1 measured at 20° C.
 114. The kit of claim 111, in which thecontainer containing a water insoluble calcium silicate further containssilicon containing fibers with a length of less than 1000 μm.
 115. Thekit of claim 111, in which the container containing a water insolublecalcium silicate further contains silica flour with an average particlesize of less than 500 μm.
 116. A process for the preparation of aninorganic binder having calcium silicate sites which are connected theone with the other by alumina-silica phosphate bonds, the calciumsilicate sites acting as cross-linking sites for the alumina-silicaphosphate bonds with a weight ratio Al₂O₃/SiO₂ ranging from 0.3:1 and10:1, in which water insoluble calcium silicate particles are mixed withan acid alumina-silica phosphate solution at a temperature lower than50° C., said acid alumina-silica phosphate solution comprisingsolubilized SiO₂ and having a pH of less than 2, said alumina-silicaphosphate solution having a weight ratio Al₂O₃/SiO₂ ranging from 0.3:1and 10:1.
 117. The process of claim 116, in which water insolublecalcium silicate particles are mixed with an acid alumina-silicaphosphate solution at a temperature lower than 50° C., said acidalumina-silica phosphate solution comprising solubilized SiO₂ and havinga pH of less than 1.5, said alumina-silica phosphate solution having aweight ratio Al₂O₃/SiO₂ ranging from 0.6:1 and 6:1.
 118. The process ofclaim 116, in which water insoluble calcium silicate particles are mixedwith an acid alumina-silica phosphate solution at a temperature lowerthan 50° C., said acid alumina-silica phosphate solution comprisingsolubilized SiO₂ and having a pH comprised between 0.5 and 1.5, saidalumina-silica phosphate solution having a weight ratio Al₂O₃/SiO₂ranging from 0.6:1 and 6:1.
 119. The process of claim 116, in which theweight ratio water insoluble calcium silicate particles/solubilized SiO₂present in the alumina-silica phosphate solution is greater than
 1. 120.The process of claim 116, in which the weight ratio water insolublecalcium silicate particles/solubilized SiO₂ present in thealumina-silica phosphate solution is greater than 1.5.
 121. The processof claim 116, in which the calcium silicate particles are calcium metasilicate particles having a substantially acicular nature with alength/diameter ratio from 2/1 to 50/1.
 122. The process of claim 116,in which the calcium silicate particles are calcium meta silicateparticles having a substantially acicular nature with a length/diameterratio from 3/1 to 20/1.
 123. The process of claim 121, in which thecalcium meta silicate particles have an average length from 10 μm to 10mm.
 124. The process of claim 122, in which the calcium meta silicateparticles have an average length from 50 μm to 5 mm.
 125. The process ofclaim 116, in which the calcium silicate particles act as cross-linkingsites for alumina-silica phosphate bonds.
 126. The process of claim 116,in which the weight ratio calcium silicate particles/alumina-silicaphosphate solution is comprised between 0.1 and 1.1.
 127. The process ofclaim 116, in which a filler is mixed with the calcium silicateparticles before being mixed with the acid alumina-silica phosphatesolution.
 128. The process of claim 116, in which a filler is mixed tothe mixture calcium silicate/alumina-silica phosphate solution, beforeits hardening.
 129. The process of claim 116, in which the hardening ofthe binder is carried out at a temperature comprised between 0° C. and50° C.
 130. The process of claim 116, in which the binder is hardenedunder pressure.
 131. The process of claim 116, in which the amount ofcalcium silicate added to the acid silica alumina phosphate solution issuch that the weight ratio calcium silicate/SiO₂ present in the acidsolution is comprised between 1 and
 5. 132. The process of claim 116, inwhich the amount of calcium silicate added to the acid silica aluminaphosphate solution is such that the weight ratio calcium silicate/SiO₂present in the acid solution is comprised between 1.5 and 3.5.
 133. Theprocess of claim 116, in which the amount of calcium silicate added tothe acid silica alumina phosphate solution is such that the weight ratiocalcium silicate/SiO₂ present in the acid solution is greater than 2.134. The process of claim 116, in which the acid silica aluminaphosphate solution is prepared by mixing a silica-alumina mixture withan acid consisting substantially only of phosphoric acid.
 135. Theprocess of claim 134, in which further silica and alumina is added tothe formed acid solution.
 136. The process of claim 116, in which theacid silica alumina phosphate solution is prepared by mixing silicaparticles with an acid consisting substantially only of phosphoric acid,and by mixing thereafter to the silica containing solution aluminaparticles.
 137. The process of claim 116, in which the acid silicaalumina phosphate solution is prepared by mixing alumina particles withan acid consisting substantially only of phosphoric acid, and by mixingthereafter to the alumina containing solution silica particles.
 138. Theprocess of claim 116, in which the acid silica alumina phosphatesolution is prepared at least by mixing precipitated silica with an acidsolution with a pH lower than 1.5.
 139. The process of claim 116, inwhich inert silicon containing fibers with a length of less than 1000 μmare mixed to the mixture calcium silicate/alumina-silica phosphatesolution, before its complete hardening.
 140. The process of claim 116,in which inert silicon containing fibers with a length of less than 1000μm are mixed to the alumina-silica phosphate solution before the addingof water insoluble calcium silicate particles.
 141. The process of claim116, in which inert silicon containing fibers with a length of less than1000 μm and water insoluble calcium silicate particles are addedtogether to the alumina-silica phosphate solution.
 142. A process forthe manufacture of a product comprising a support provided with at leasta hardened layer comprising an inorganic binder having calcium silicatesites which are connected the one with the other by alumina-silicaphosphate bonds, the calcium silicate sites acting as cross-linkingsites for the alumina-silica phosphate bonds with a weight ratioAl₂O₃/SiO₂ ranging from 0.3:1 and 10:1, in which at least partly a faceof the support is contacted with a composition before its completehardening, whereby said composition comprising at least: an inorganicbinder having calcium silicate sites which are connected the one withthe other by alumina-silica phosphate bonds, the calcium silicate sitesacting as cross-linking sites for the alumina-silica phosphate bondswith a weight ratio Al₂O₃/SiO₂ ranging from 0.3:1 and 10:1, and afiller, and in which the composition is hardened on said support. 143.The process of claim 142, in which the composition contacting thesupport comprises silicon containing fibers with a length of less than100 μm, the weight content of silicon containing fibers with a length ofless than 1000 μm in the composition after its hardening and afterremoval of the possible free water being of at least 0.5%.
 144. Theprocess of claim 142, in which at least a portion of a face of thesupport not contacted with the composition is provided with a waterrepellent coating.
 145. The process of claim 144, in which the waterrepellent coating is a fluoro silicon coating.
 146. The process of claim142, in which at least one face of the support intended to be notcontacted with the composition is provided with a water repellentcoating.
 147. The process of claim 146, in which at least partly a faceof the support is provided with a water repellent coating priorcontacting at least partly a face of the support with the composition.148. The process of claim 142, in which at least a portion of a faceadjacent to a portion of a face provided with a hardened layer areprovided with a water repellent coating.